Telephone-exchange system.



M. L. JOHNSON. TELEPHONE EXCHANGE-SYSTEM. APPLICATION FILED JULY 15,1912.

1, 1 l 6,5 38A. Patented Nov. 10, 19M.

1 SHEETS-SHEET l.

OQ E 1f VVITNESSES v INVENTOR MORTON L. JOHNSON 77M BY AT T ORN EY M. L.J'GHNSON. TBLEPHUNE EXCHANGE SYSTEM. APPLICATION FILED JULY 5, 1912. Ll1 6,538; Patented Nov. f0, i914.

4- sREETs-SHBBT 2.

FG@ 2 1NVENTOR MORTON L. JoHNSoN ATTORNEY M. L. JOHNSON. TELEPHONEEXGHANGE SYSTEM.

`APPLIAI'IONl FILED JULY15 191'2.

ji y El l 6,538, Patented NOV. 10, 1914.

IlA SHEBTS-SBBET 3.

i l JOHNSON M W JVM EW ,MORTNL.

ATTORNEY M. L. JOHNSN. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED JULY1s, 1912.

Patented Nov. l0, 1914.

4 SHEETS-SHEET 4.

y eraloly in www ritter@ it .it le ith/tf'llltilliil tlllFICE.

LEpeciicel'on of Letters Patent.

Application filed Jl'uly l5?, 1.9i?.

v cation.

My *invention relates to telephone eli-- change systems and has jor oneits oir-- ject-s the provision ot a telephone exchange system having' aplurality of operators positions, at which are located signals,telephones, or other responsive devices, the.

provision of conductors extending from these responsive devices toselector mechanism, and means goveriied hy calling,r lines whereby suchselector mechanism may be set into operation. for the purpose ofe'i'ecti ings; cooperative relation between the calling lines and saidconductors whereby the opcraters may become apprised of the numbers olthe calling,I lines,there boing' link connectors having1 operatorcontrolled means to adapt them to their line joining function'independently of said selector mechanism.

`l desirsbly supplement this equipment by the provision of supplementalselector mechanism for enablingl the aforesaid selector mechanism tobecome operatively associated with conductors that 'le-ud. to thepositions oi: operators Who are free to set up connections betweencalling and called lines.

My invention has for another of its objects the pro-vision of meansassociated with calling lines for creating cha acteristic sig nais, theemployment ot sigi'lal receivers and the provision of selector mechamsmfor operatively .associating idle signal receivers with calling lines-soas to enable such signal .receivers to receive the characteristiccalling1 line signals. The signal rec yivers are pret'u thetorm oirecording devices so that the numbers of the calling;r lines may he madea n'iatter ol record. ln the preferred embodiment o'l he invention thesesignals are associated in the presence oi" the operators so. that the orrators do oet need to inquire oi the vcalling suhs; fillers the immbersci? their lines' l Will explain my invention more fully oy :reference tothe accompanying drawings' showing the preli'erred embodiment thereof,to `which l do not wish to be limited, and in which-- Figure l is a verygeneral diagrammatic vievfv illustrating the general principles of theinvention; and Figs. 2, 3 and 4: taken collectively illustrate thepreferred equipment and circuit arrangements that enter into theembodiment of the invention illus tinted.

4lltele,r'ring tiret to Fig. l, l have shown two telephone stations 2land 22 Whosev lines, in the embodiment of the invention illustrated,extend todiiierent sections of a multiple switch board where the linesarel connected with multiple jacks l., 2, though l do not limit myself.3in the embodiment of my invention shown to a multiple switch boardsystem.

The telephone lines are divided into groups, say of titty lines cach,and a. plurality, say two, of linder switches 3 are common to the linesot' each group, each finder switch having as many sets of Wait ing`contacts as there are lines in the group,

Aeach finder switch beingl accessible to each line in the group. Thestations el and 22 are illustrated as being included in such a. group.As the invention is embodied in its simplified lorm for the purpose ofdisclosure, the line relays oit twenty-five of the lines are adapted to`set one of the finder switches into operation and the line relays ofthe-remaining lines are adapted to set the other Ahinder switches intooperation, cach line relay setting its associate finder switch intooperation when it is energized upon the removal of the telephonereceiver from the switch hook of the calling;` station' to which suchline relay is individual. lVhen an actuated finder switch has come' intoassociation with contacts ol the line' whose line relay caused itsoperation such linder switch causes the oymratiou of an op craterselector switch l which continues in operation until it becomesassociated with the contacts olf conductors leading to an operatorsposition where the operator -iS at lihcrty to establish connectionbetween call- .ing/ and called lines.

105. lllg. l shows three operators positions tor connects the callingand called lines and ""my invention very important and do not vI`hecalled lines of course may be in another of the' calling line (later tobe described) to Ythe incoming calls is to be kept then the in- B, C atwhich ordinary manual equipment is illustrated for the purpose ofuniting calling and called lines which both may be in the group, havingthe stations 21 and Q2.

group or system that may or may not be equipped with the apparatus ofthe invention, such other lines being illustrated as extending tostations 900 and 950 and which lines have multiple jacksf, G at theoperators positions. When the conductors leading to the position of anidle operator are selected by the operation of an operatorselectorswitch 4, the recorder 7 at Vsuch position-.is set intooperation by the equipment recordv the number of the calling line in thepresencelof thedoperator who thereupon connects the answering end of alink connector or cord circuit with the calling line and thereafterlinde the number of the line which is desired, such operator thereafterconnecting the called end of the link con,- nector or cord circuit withthe called line. As I have embodied the invention the operacommunicateswith the calling subscriber and has supervision over the connection inaccordance with well established /manual telephone exchange practice,though I do not limit the adaptation of the invention to such manualtelephone` exchange practice. The recorders 7 are selectively orinterchangeably associated with calling lines,'a recorder beingappropriated by a calling line to the exclusion of other calling lineswhereby a record of th-e calling line is made Without interference byother calling lines and I believe this characteristic of my invention tobe broadly new. The recorders 7, in the invention illustrated, serve toannounce the calling lines to the o-perators'visually but when they areemployed for the operators",` use it is obvious that the informationvmay also be conveyed audibly by the operation of the instruments 7. Nhen the record of struments are in the form of recorders and need notthen be located 1n the presence ot the operators. I considerthis featureof Wish to limit its employment to systems having other characteristicsherein set forth.

Referring now to Figs. 2 to linclusive, these figures should be readwith the conductors illustrated at the tops thereof in alinement, thefigures being arranged in numerical order. I will describe a connectioneffected between calling station 21 and called station 900 which iseffected by means of the apparatus shown in the upper halves of Figs. 2to; 4 inclusive. The equipment at the telephone stations 21 and 22, 900and 950 is that which is ordinarily 'found at the subscribers" stationsin ordinary manual telelphone exchange systems. The lines which 'extendfrom these stations, are provided with well known line equipment and thelink connectors for uniting the lines in conversation are of well knownconstruction and arrangement, though it is to be understood that I donot-A limit myself to these well known characteristics of station andline equipment. Each telephone station shown includes a switch hook 8having a normal contact through which it closes' a bridge containing abell 9 and condenser 10 and an alternate contact through which it closesa bridge containing a telephone receiver 1'1 and transmitter 12. Whenthe telephone bridge is closed the `line relay 13 has circuit closedtherethrough that includes the grounded common battery 14, the contactsof the ordinary cutoff relay 15, and the contacts of an additionalcutoff relay 16 which I add to.

tacts of the line relay are thereafter included in the circuitassociation to be described. Normally the grounded armature switches ofthe normally inert line relays 13 are connected with waiting contacts 15of each switch 3,` each switch having` a contact 15 individual to eachof the lines. Vhen ground is present upon contacts 15 the finderswitches 3 will not stop at such contacts. But when the line relay 13 isenergized in response to a subscribers initiation of a call, ground. isremoved from the Contact 15 of cach of the switchesa 3 individual vtosuch line so that the finder' switch set into operation may stop atsiich contactsi.

The circuit established when the line relay of a calling line isenergized may be traced from the grounded armature switch dir ,suchrelay, the alternate contact of'such switch, the lower armaturelswitchof relay 17 common to twenty-tive of the lines and individual to oneswitch 3, taps being vindicated at 18 leading to the alternate contactsof the line vrelays of the other twenty-four lines (the relay 17 as awhole of course being common to the twenty-Eve lines and individualV tosaid switch 3), the normal contact of the lower armature switch of relay17, the relay 19, to the grounded common battery 14L through the sideswitch wiper 20. The upper grounded armature switch ofA relay-19 isthereupon moved to establish a circuit that may be traced from itthrough its contact,.the armature 'switch of sluggishly operatinginterrupter relay 23, the rotary magnet 24,' the side switch wiper 20,to groundedbattery 14. The rctary magnet 24 thereupon operates to rotatethe wipers 25, 26, 27, 28, 29, 30 until the wiper 26 engages the contact15 that has been freed from ground by the enerwww@ lil pieve@ 'meglleg 3el reid W nmifnelg lic plece lle .wle ma'i'iel; wpel ,w 33 in cemlilenle be moved lie l H eeemlil `peellexe upon lgllc fjleneilg@Malen el theprim-,e megl'let 3l, this fleece gznlcm occurring when llxe associatewlj cemrlers che ungrmuvled ceetect le Vlucl le ille Call" lime, lf"

l culell' 1 cul es ce ll weee/fl ffmc the cee. e llu:5ll';l'l m cil thisbelief welle@ fr il e Falle cf v cuj/ c aegee, thereby; lie elle egg;ite gmnn=-lell ccnl#- Ll le 'llmu cui out eseeclellje ccnl'ccc iii elfl'f me again gmfmnlumlefl l rl mmf nel; Se cel; uil: dl wmileel armeni;-es'lclifllisllefl n elim; S1 itch and lll@ l 'with che tell' e' echtemc; elle :aule el? 'lille calling line, l l1 the upper Wmllf 'l ley 3G'le md5 lle circuit ec cem et, llmmggll the glreunle belle@ le? llelower Winding of relay 36, 'the Llppeli' eme el lvlle lewe? meneameswitches el 1*. 'T nml alle Wiper which new Wltl'l lcelll'mg clmlzeelzcommet,

4:5 Ollez eide e115 each line lm lect; 1 1 eecl'l ew 'in bridge el lilleand lgleeyelfolje tela. eil ',#felejy 8G lie the ywel 1; 'i7 nml fcmrgmccl 'lflixe upper @menue-:l :wma-- @ture switch relay 36 ie newnlclml' l m @lll the elements B6 38, 39 and the 'Wms el() te fillinclusive are parte, -:Ehe SW1' lch l shown et the top el Fig, 3, beingindividual lo lzlle switch 3 shown at the tcp of Fig. 2. The privatemagnet e115 is energized pen the initial movemelll: of l'he reln'rjf311:1 wel, 39 enel denergzed when the Wine? l tefe eci/)meis :Elem whichglemnl lms I enloved, mil when the 'Wiper lf2 e euch ungmuzncled. commettlm Wipers Jl() and lll are 'nevel'l lien, ille wiper ele@ llzee mpemlndelf the 'clergy' meg'nel; 39 'to slop 'li-lle mme mem el' the wlpeel,lil le (l-fl; l 'llllgjer in ile Secund pesllcn, plecec lille,gy'f'clmrl eeeblieleil by lle el fem s lmfel mmctue' switch el 1f' l;epee the commet mgegefl by lille w and ether centecte elllel :,'Wl mult.i related therein, it beil'lg medew-lem tlml; the contacte ef theswilsclwee 4iv ever Wlleli lie .Wipers @il te f ll ll'lcluslve Wl ik areir'zmllaiply celmul, this applying te eccll cecliflcts hee l thai; me rwith pil I el? peil-e ell nlila 'llml elle @Helmet-cys l epeeleepesiatlene te lle ceieneelefl wich lf'wecng cem 'the switches ll the 1eopelell/eljr with a plurality olf paire of ewteher The greunfled-centeets of the Wl of 'lle dillfelent switches lef the serve to meimeinthe cil-cell; ollzlle megeebs 1-5 ef @they operator switches Ll so es teprevent the side switches ef ether operator selector switches; il :fromstepping 111e second positions enel 'tllex'eby lcllucle Upenrtheconnection with @pew Wlrc has been selected. llfhen he ewelx Wiper l0 ofthe actuelle@ eperalm selectin switch l has been brought imc milposition ecul; iecleseal tluouq'l ewlbchng relay l? te bz'lflg the mtime'c ew. .ches ci' this relay into engagement tefminal contacts of fallelzelli. Strandes ci? said selector switch 4f, which milking 556m meconnected with the wipers; llil. nml, The talking lcrzull is coctlmueflrcm wipers ll and. 43 the c-:mdlzclere 1M), that, in his instance,terminal-,e switch springs of .en eperelo's Esteem@ j The {gue'elingg'emulezl cemleciien tnblished by the wiper 42 includes elle nel device5l and the grounded bnliterj ll:i the il nel Signal 5l being individuelte the lejf, lic. lll/lien alle Signal 5l le caused le glow che 12eepemtefr may manipulate hel listening" lvl-ey le inclufle thetelepl'lmle oulllt 52 'En ine pllec circuit relation W e culling eecl'lberc lme lao zle'certem the Amber ITL felled lme desueel. the'epere'lz-Y lsllell el: me lv@ same timel ascertaining` the number of'the calling line and establishing connection between the calling` andcalled lines with the agency of the ordinary form ot link connectorwhich l hare employed and which includes an answering plug 53 forinsertion within a multiple jack connected with the calling line and aconnecting plug 5l for insertion within a multiple jacl; ot the calledliuc. The cord circuit may be provided with the usual supervisory signalapparatus and the operator will take down the connection when theparties are through in response to signals conveyed inthe usual main nenln the preferred embodiment ot my nreution the recorders or calling lineenunciators are located at the operators posii 'tions and serre7 bymeans of the mechanism and circuits tA be describe/dmautomatically to degirate to the operatdi' the nuinber or the calling line. lllhcn therecorders or enunciators 55 are thus placed at the operators positions,the operator, after depressing the associate listening key 50, merelyiin uires'the number ot the line wanted7 already having been furnishedwith the number of the calling line by the associate device 55, lheconnection is then put up between the calling and called lines in theusual way.

Still referring to the upper parts of Figs, 2 to l inclusive, therecorder or enunciator 55 may be ot the ordinary telegraph pen registertype. lt may be included in a local circuit governed by a relay 5G, thecircuit for this relay being traceable from the grounded battery lethrough the conductor 5T to the contact then engagedby the wiper Llei,the conductor 58, the armature switch 59 of relay 47 and its thenengaged contact, the conductor (Si), the armature switch 6l of relay 35,the conductor 62, wiper 29, the signal sending switch arm 63, to thegrounded contacts Gl oyer which the arm (53 is passed to gire the relay56 a characteristic operation that is peculiar to the callingv line andwhich correspondinglycauses the register 55 to operate to record thenumber of the calling line. The contact arm 63 is carried upon the shaftot the ratchet wheel G5, and the ratchet wheel G5 is caused to beoperated by the armature of' the magnet 66. The circuit of thisarmatureA includes the grounded battery llh thev circuit interrupter 67;the switch arm 68 upon the shaft ot the wheel 65, the segmental Contactengaged by tn e arm' 68, the upper armature switch of relay G9 that isnow energized through a circuit that includes -the grounded battery le,the wiper 30, the lowerniost armature switch of relay 35, and thelowerni'ost armature switch of lrelay el' to ground. The wheel is driventor the purpose ot driving thearms 63 and 68h57 means et the sie .ma-l.

,ses

segmental Contact so as to open the circuit ot' the magnet (Jil, causingthe wheel G5 to come to rest. rhe wheel (l5 is restored to normal bymeans ot a spring TO when the holding dog Il is drawn out of engagementwith the wheel. l magnet 72 operates upon the dog 7l. to withdraw itfrom the wheel 65 when the switch. arms 63 and 68 hare Inorcd throughtheir ranges ot travel, the magnet Z2 being included in closed circuitvwhen the magnet 59 is denergizeu@upon the release and restoration ci thefinder and operator selector switches as will later appear. lllhen themagnet G9 is dcnergized the circuit established tor the magnet 72 may hetraced from. the grounded lower armature switch of magnet 69 through themagnet 725 the otl normal contact switch 73 whichis closed immediatelyafter the wheel (35 is started into operation, to grounded battery il.The spring now serves to restore the wheel 65 and the switch arnis 63and 68 to normal.

lWhen the operator inserts the answering or calling subscribers plug inthe multiple jack of the calling line, the finder and opo craterselector switches that were employed in selecting the operator arerestored to normal as a consequence of the circuit then establishedthrough the cutod relay l5, the re lationship of this cutoti' relay, theplug and the jack receiving the plug being in accordance with commonmanual telephone eX- cl ange practice. The relay l5, when energized,`opens theline' circuit at its contacts and therefore causes thedenergization of the relay 36. rlhe lower armature switch of relay 36,in engaging its normal contact, establishes circuit through the releasemagnet 7st and the previously closed oil normal switch 7 the wipers l()to il inclusive and t6 to norllllhen the lower armature switch ot relay3G is disengaged from its alternate contact the ground is removed fromthe relays l?, and L7 to restore these relays to normal. rllhe upperarmature switch of the now denergized relay l? establishes circuitthrough the release magnet 76 and the previously closed ci? normalswitch 77, this circuit including the grounded battery letI and theupper released armature switch of relay 234. The magnet 7G causes theyipers 25 to 30, inclusiven and 20, 3Q and 33 to restore to normal.lVhen the relay e? is denergized its lowerniost armature switch isdisconnect ed from ground to open the circuit of the relay 69 wherebythe release circuit for mag- `net '72 is established with the resultsthatl `'have been described7 this release circuit be- 'llhe releasemagnet .74 restores lll) ' dash contacts individuel to line ,linee esting opened. hy the Wheel when it reaches normal position.

The equipment shown in the lower halves of Figs. V2, 3 sind l operatesin the some man ner as the equipment shownin the upper halves of thesefigures end similar ports having similar functions aire given similarcharacters of reference. lhe contscts tS-'l pertaining to the lowerfinder switch 3 in Fig. 2 are different from the contacts till in theupper switch 3 oi. Fig'. 2 since the ccntucts 64A individual to euchline ere iol the purpose of conveying signals peculiar to theirlinesy'the flesh end dot contacts individuel to line 21 causing thereg,D l:ter 55 l1-liet is selectively associated with seid line toregister the number Ell while the double causo the register 55 that isselective-i1;Y associated with seid line toregister the number QSL lnthe preferred embodiment the elter-- nete contacts of' the urinctureswitches of relays 13 of the Erst twenty-'live lines are connected withthe lower .iurineture switch ot relay 17 of one oit the switches il,While the alternate contects oi the ztrineture switch ci relays 13 ofthe second twentylire lines ere connected with the lower armature s itchof relay 17 oii the other switch The elternete contact of the lowerswitch oli relsv 1? of one switch 3 is connected with the lower armatureof relay 1i' of the other switch 3 end vice verse. 'lhus it eitherswitch 3 busy the companion switch. Sl will take cere of the second culloi? any oil. the other re meining lines in the group of The signalreceivers enable the ccononiicsl distribution oit the treiiic und re ider unnecessary the et iipnient oi line nels and answering je,individual to the lines. This lfeziture oit the invention is of servicesirrespective oit' Jhe clmrecter ott the selector mechanism thatselectively esseciste the signal receivers with their lines.

The recording arrangement illi'lstretedneed not be further described inview ci the Well known state of the srt Reference may be had to AmericanTelcgmpz. oy "5"' liain Mever, dr.9 of 1909.

llt is not thought necessary to illustrate the mechanical constructionoit the switches 3 and 4l. Materiel parte oie the mechanism find counterparts in the structure shown upon .page 530 et Ven lleventeslelepmnology published in 1910., the vertical magnets and the movementsthey etlect l eing omitted. The i. l icel consternation is furtherexemplifies legi' ich Potent The ete'tio scrilcere not te .le

The

tor provided with Waiting contacts upon eech oit the operator .selectorswitchee end the contacts et each :are multiplied. with. the contacts ofthe other sets.

lfllllile l lieve herein shoe/n und perticulerly dcscibed the preferredeinllodiu t of inf; inven rciel do not Wish to be linnted to "he4precise details ot construction end cir cuit errengemcnt illustratedchunges muy readily hey :rotule without depui-ting troni the spi it oimy invention, but

levinig thus described my invention, l claire new end desire to secureby. Let ters lstent the l'ioliowingr'm il. telephone exchange systemiiuzludingg lines extending* from telephone stations to en e'iicnenge;operators responsive devices located et diilierent operators positions;

r switches operetivelli)f ussocieteol conductors leerling operators fsive c "ies sind serving seele ell .ig lines sind u seid conductors;ineens ociuted with teltqihone lines for situee' seidv selector switchesinto operation when the lines are ceiling lince;A additional selectorswitches interposed. between the aforesaid selector switches end theaforesaid coiiduc'zors for associating the e'firesoid selector switcheswith the conductors that are Afor selection; link connectors havingoper-- eter controlled ineens to adopt there to their line joining;pfunction independently oi. seid selector switches; sind ineenscontrolled by seid linli connectors 'tor releasing the selectorswitches.

.fi teleplfione exchange system includineu lines rtending irom telephonestations to en e; lange; operators responsive devices located etdiilerent operators positions; sew lector switches operativelyassociated 'with conductors leading to the operators responsive devicessind serving; when opei'eted 'to seek celling lines and associate themwith said conductors; ineens associated with the telephone lines forsetting seid selector switches into operation when the lines are cie.tlieni celing lines; udditionsl selector switches' conductors leading tothe operators responsive devices and serving when operated to seekcalling lines and associate them with said conductors; means associatedwith the telephone lines for setting said selector switches intooperation when the lines are calling' lines; additional selectorswitches interposed between the aforesaid selector switches and theaforesaid conductors for associating the iirst aforesaid selectorswitches with the conductors that are tree t'or selection, theadditional selector switches having means operated thereby when releasedthat then serve to release the iirst aforesaid selector switches; andlink connectors having operator controlled means to adapt thein to theirline joining function independently of sain selector switches* et. itelephone exchange system including lines extending trom telephonestations to an exchange; operators resoonsive devices located atdiiierent operators positions; selector s "itches operatively associatedwith conductors leading to the operators respon` sive devices andserving when operated to seek calling lines and associate them with saidconductors; means associated with the telephone lines for setting saidselector switches into operation when the lines are calling lines;additional selector switches interposed between the aforesaid selectorswitches and the aforesaid conductors for associating the firstaforesaid selector switches with the conductors that are tree forselection, the rst aforesaid selector` switches including' meansoperated thereby to cause the operation of the second selector switches,the additional selector switches having means operated thereby whenreleased that then serve to release the rst aforesaid selector switches;and link con` nectors having operator controlled means to adapt them totheir line joining futction independently ci said selector switches.

5. A telephone exchange system including lines extending from telephonestations to an exchange; operators responsive devices located atdifferent operators positions; se` lector switches operativelyassociated with conductors leading' to the operators responsive devicesand serving when operated to seek calling lines and associate them withsaid conductors; means associated with the telephone lines for settingsaid selector switches into operation when the lines-are calling lines;additional selector switches interposed between the aforesaid selectorswitches and the aforesaid conductors for associating the lirstaforesaid selector switches with the conductors that are tree forselection, the additional selector switches having means operatedthereby when released that then serve to release the lirst aforesaidselector switches; operator controlled means tor releasing the secondaio-re said selector switches; and link connectors having operatorcontrolled means to adapt them to their line joining Jfunctionindependently of said selector' switches.

6. A telephone exchange system including lines extending from. telephonestations to an exchange; operators responsive devices located atdifferent operators positions; selector switches opeatively associatedwitl. conductors leading' to the operators7 responsive devices andserving when operated to seek calling lines and associate them with saidconductors; means associated with the telephone lines for setting saidselector switches into operation when the lines are calling lines;additional selector switches interposed between the aforesaid selectorswitches and the atoresaid conductors for associating the lirstaforesaid selector for selection;n the `tirst aforesaid selectorswitches including means operated thereby to canse the operation of thesecond selector switches, the additional selector switches having meansoperated thereby when released that then serve to release the-firstaforesaid selector switches; operator conn trolled means tor releasingthe second atoresaid selector switches; and link connectors havingoperator controlled means to adapt them to their line joining functionindependently of said selector switches.

7. A telephone exchange system including lines extending from telephonestations to an exchange; operators responsive devices located atdifferent operators positions; selector switches operatively associatedwith conductors leading to the operators responsive devices and servingwhen operated to seek calling lines and associate them with saidconductors; means associated with the telephone lines for setting saidselector switches into operation when the lines are callinglines;operator controlled means for releasi g selector' switches; andlink connectors having operator controlled means to adapt them to theirline joining function independently of said selector switches andforming part of said operator controlled means.

8. A telephone exchange system including lines extending from telephonestations to an exchange; operators responsive devices lector switchesoperatively associated with conductors leading to the operatorsresponsive devices and serving when operated to seek calling lines andassociate them with said conductors; means associated with the telephonelines for setting said selector switches into operation when the linesare calling lines; additional selector switches interposed between theaforesaid selector located at different operators positions; se-Iswitches with the conductors that are fre@ are free -for selection withthe means for producing characteristic signals; and means for effectingthe opeiation of the selector mechanism.

16. A 'telephone exchange system including telephone lines extendingfrom telephone stations to anfexchange; means indi 'vid'uai to the linesfor producing characteristie signals to distinguish calling lines fromeach other; signal receivers located at dif- 4 ferent operatorspositions; seec'tor mecha- I Copies oi h patent may be obtanef for fivecents each, 'by addressing Jhe Gummi-sammler oi Patents,

Washington, D. G.

